Grandma said that since her birthday is on February 29, which only happens every four years, she calculates her age as 20, not 80.

Are you a word wiz?

Take a calculated risk, and tell us which of the following answers you think gives the correct origin of "calculate."

A. It comes from a Dutch word meaning "to count."

B. It comes from an Arabic word meaning "the stars."

C. it comes from an Old English word meaning "to build up."

D. It comes from a Latin word meaning "pebble."

In Latin "calculus" meant "pebble." Add that information to the fact that the Romans used pebbles to do calculations on a counting board and you'll see how "calculus" became associated with math. "Calculus" gave rise to the verb form "calculatus," meaning "calculate." It's not hard to figure how a word meaning "to find by performing mathematics" would acquire the additional meanings of "estimate" and "plan by careful thought." And that about sums it up for "calculate."